Chapter 18: Problem 29
How does the formation of lactate permit glycolysis to continue under anaerobic conditions?
Short Answer
Expert verified
The formation of lactate regenerates NAD+, allowing glycolysis to continue and produce ATP under anaerobic conditions.
Step by step solution
01
Understanding Glycolysis
Glycolysis is a series of reactions that convert glucose into pyruvate, producing ATP and NADH in the process. This pathway occurs in the cytoplasm and does not require oxygen.
02
Anaerobic Conditions
Under anaerobic conditions (lack of oxygen), the electron transport chain cannot operate. As a result, NADH builds up since there is no oxygen to accept electrons and regenerate NAD+.
03
Role of NAD+ in Glycolysis
NAD+ is an essential coenzyme that is reduced to NADH during glycolysis. Without sufficient NAD+, glycolysis cannot proceed, halting ATP production.
04
Formation of Lactate
To regenerate NAD+ from NADH under anaerobic conditions, pyruvate is converted into lactate by the enzyme lactate dehydrogenase. This conversion oxidizes NADH back to NAD+, allowing glycolysis to continue.
05
Permitting Glycolysis to Continue
The regeneration of NAD+ through the formation of lactate ensures that glycolysis can continue to produce small amounts of ATP, even without oxygen. This is crucial for cells that rely on anaerobic respiration for energy.
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with Vaia!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Anaerobic Respiration
Anaerobic respiration is a process that cells use to generate energy without the presence of oxygen. This type of respiration is crucial for environments where oxygen levels are low or unavailable. During anaerobic respiration, glucose is broken down through glycolysis in the cytoplasm to produce ATP, which provides energy to the cell.
Under aerobic conditions, pyruvate produced from glycolysis would enter the mitochondria for further energy extraction via the Krebs cycle and the electron transport chain. However, in anaerobic conditions, the lack of oxygen halts the electron transport chain.
The main function of anaerobic respiration is to ensure that cells can still produce ATP in environments deprived of oxygen. This allows organisms to survive in various conditions and continue to perform vital biological functions.
Under aerobic conditions, pyruvate produced from glycolysis would enter the mitochondria for further energy extraction via the Krebs cycle and the electron transport chain. However, in anaerobic conditions, the lack of oxygen halts the electron transport chain.
The main function of anaerobic respiration is to ensure that cells can still produce ATP in environments deprived of oxygen. This allows organisms to survive in various conditions and continue to perform vital biological functions.
NAD+ Regeneration
NAD+ (nicotinamide adenine dinucleotide) is a key coenzyme in glycolysis, playing an essential role in redox reactions. It accepts electrons and gets reduced to NADH during glycolysis. The continuation of glycolysis requires a steady supply of NAD+, which is typically regenerated by the electron transport chain in the presence of oxygen.
In anaerobic conditions, the electron transport chain is inactive because there is no oxygen to serve as the final electron acceptor. As a result, NADH accumulates, and there is a shortage of NAD+, which is critical for glycolysis to proceed.
In anaerobic conditions, the electron transport chain is inactive because there is no oxygen to serve as the final electron acceptor. As a result, NADH accumulates, and there is a shortage of NAD+, which is critical for glycolysis to proceed.
- To overcome this, cells employ alternate pathways to regenerate NAD+ from NADH.
- One such pathway involves the conversion of pyruvate into lactate.
Lactate Formation
Lactate formation is a key biochemical response to anaerobic conditions that enables continuous ATP production through glycolysis. When oxygen is not available, pyruvate cannot enter the mitochondria for further aerobic breakdown. Instead, pyruvate is converted into lactate via the enzyme lactate dehydrogenase.
However, the accumulation of lactate can lead to muscle fatigue and soreness during intense exercise. The body can clear lactate from the bloodstream when oxygen becomes available again, converting it back to pyruvate for further metabolism.
In summary, lactate formation is an adaptive mechanism that ensures glycolysis can continue under anaerobic conditions, allowing cells to generate ATP and maintain cellular functions.
- This conversion is crucial because it regenerates NAD+ from NADH.
- Without this regeneration, glycolysis would halt due to insufficient NAD+, and ATP production would stop.
However, the accumulation of lactate can lead to muscle fatigue and soreness during intense exercise. The body can clear lactate from the bloodstream when oxygen becomes available again, converting it back to pyruvate for further metabolism.
In summary, lactate formation is an adaptive mechanism that ensures glycolysis can continue under anaerobic conditions, allowing cells to generate ATP and maintain cellular functions.